1. Field of the Invention
The present invention relates to a semiconductor chip and display panel using the same, and more particularly, to a semiconductor chip and manufacturing method thereof which can improve the remaining ratio of anisotropic conductive particle, and a display panel using the semiconductor chip and manufacturing thereof.
2. Description of the Related Art
As flat panel displays, which are popular as a display device, there are a liquid crystal display (LCD) using a liquid crystal, a plasma display panel (PDP) using a discharge of an inert gas, and an organic electroluminescent display (OLED) using an organic light emitting diode. Among these displays, the PDP is applied to large-sized televisions (TVs), whereas the LCD and OLED are applied to many fields in various sizes ranging from small to large-sized products, such as cellular phones, notebook computers, monitors, TVs, etc.
Such a flat panel display includes a display panel having a pixel matrix for displaying images, and a panel driving circuit for driving the display panel. The panel driving circuit is integrated in a semiconductor chip shape and then electrically connected to the display panel. To connect such a driving circuit chip (hereinafter, referred to as a driving chip) to the display panel, a tape automated bonding (TAP) method and a chip-on-glass (COG) method are typically used.
The TAP method is to attach a tape carrier package (TCP) or chip-on-film (COF) on which the driving chip is packaged to the display panel by using an anisotropic conductive film (ACF). The COG method is to directly package the driving chip to the display panel by using the ACF and this method is mainly applied to the display panel necessitating low cost, small size, and thin thickness.
FIG. 1 illustrates a terminal part of a driving chip packaged on a substrate of a display panel by the COG method.
Referring to FIG. 1, a driving chip 20 is electrically connected to an electrode pad 12 formed on a substrate 10 of the display panel through an ACF 15 and attached to the substrate 10 through the ACF 15.
In more detail, the driving chip 20 includes a chip pad 24 formed on a silicon wafer 22, a protective layer 26 which protects the silicon wafer 22 and has a contact hole for exposing the chip pad 24, and a bump 28 which is connected to the chip pad 24 through the contact hole of the protective layer 26 and serves as a terminal.
The driving chip 20 is packaged or attached on the substrate 10 of the display panel through the ACF 15. In exemplary embodiments, the ACF 15 may include an ACF resin 14 including a conductive particle 16. The ACF 15 may be coated on a pad region of the substrate 10 having the electrode pad 12 formed thereon. The driving chip 20 is aligned, heated and pressed, thereby packaging the driving chip 20 on the substrate 10 of a display panel. The conductive particles 16 of the ACF 15 are positioned between the bump 28 of the driving chip 20 and the electrode pad 12 formed on the substrate 10 and electrically connect the bump 28 to the electrode pad 12.
The number of the conductive particles 16 between the bump 28 and the electrode pad 12, hereinafter the “remaining ratio of the conductive particles 16”, determines the connection resistance between the bump 28 and the electrode pad 12. Accordingly, the remaining ratio of the conductive particles 16 should be of sufficient quantity or level so as to ensure the reliability of a driving signal.
Since in current technology the remaining amount of the conductive particles between the bump and the electrode pad is relatively very small, a technique for increasing the remaining ratio of the conductive particles has been demanded. Although a method of increasing the amount of conductive particles contained in the ACF may be considered in order to increase the remaining ratio of the conductive particles under the bump, this method raises the price of raw materials of the ACF.